For many years, decorative chain links made of precious and semiprecious metals have been made from wire. The wire may be round in cross section or may be formed with other cross sectional shapes such as rectangular or square.
Machines have been developed which take the wire and wind it around a mandrel of a desired shape into a helix and the individual coils are then cut from the helix. The resulting link is then flattened to be substantially planar and the link will be "open".
Automatic machines may continue the process by linking the flattened links into chains of various complexity and the individual links are then closed to prevent the chain from falling apart. Jewelry chains can be assembled with single links or multiple links on an automated basis.
A "rope" chain can be made using the same type of link but generally is manually assembled since multiple links, with alternating orientation, must be assembled. Selected ones of the links are soldered closed, rather than by compression of the link. Rope chains and their methods of assembly have been disclosed in the recent patents to Benhamou, et al U.S. Pat. Nos. 4,651,517, and Rozenwasser, No. 4,934,135.
Machines for producing "rope" chain of the prior art have been disclosed in the patents to Bucefari, et al, U.S. Pat. Nos. 4,493,183, and Allazetta, et al, No. 4,503,664. As noted in these patents, such machines use, as a starting material, a metal wire of preselected cross sectional area. During the manufacturing process, the individual links may be flattened to achieve a cross section that is other than circular.